Cink owns at least a share of the 54-hole lead for the seventh time in his career on the PGA Tour. However, he has not won any of the previous six events. Cink's best finish in those events was second place, which he has done three times, most recently at the Funai Classic last October.
Chris DiMarco, who played his way onto the United States Ryder Cup team with his playoff loss in the PGA Championship last weekend, posted a 3-under 67 to move to 6-under-par 204. He shares second place with David Toms, who double bogeyed the last for a round of 69, and Tiger Woods, who scrambled his way to an even-par 70.
Rod Pampling, Rory Sabbatini and Scott Verplank, who missed out on the U.S. Ryder Cup squad, are one stroke further back at minus-5.
After weather problems over each of the first two days, players completed their second rounds Saturday morning. The entire third round was completed as scheduled on Saturday.
Cink, who was selected as one of Hal Sutton's U.S. Ryder Cup captain's picks on Monday, closed his second round with five straight pars for a 68.
He returned to Firestone Country Club's first tee for his third round and opened with a par. Cink then got going with a birdie at the second to move to 10 under.
Cink, who owns three come-from-behind wins on tour, came right back to drain a 20-foot birdie putt at the third. From there, Cink showed off an excellent short game as he parred his next nine holes.
The 31-year-old Cink two-putted for par five times and he got up-and-down from off the green four times for par.
Cink lost his drive into the left rough off the 13th tee. After hacking out of the rough, he knocked his third shot to 12 feet. He missed his par putt and moved to the 14th tee at 10 under with a two-shot lead.
Cink ran off four straight pars heading to the 18th as his challengers fell off the pace. He knocked his second shot from the right rough just over the green and chipped his third into the cup for birdie and a five-stroke cushion.
'It's nice to finish off with a birdie, but there's still a lot in front of me,' Cink said. 'I've been around the tour eight years now and I've played a lot out here, and I know that anything can happen in 18 holes. I'm definitely not counting my chickens yet.'
Woods ran off three straight birdies late in his second round to move into a tie for second heading into the third round. He opened round three with a two-putt birdie at the second, but stumbled to a bogey at the next.
The three-time winner of this event two-putted for par on his next five holes before getting up-and-down for par at the ninth.
Woods dropped an 8-iron 9 feet from the cup to set up birdie at the 10th. After his second shot hit a tree and came up short of the 11th green, Woods walked away with his second bogey of the round.
He battled back at the par-3 12th. Woods dropped his tee shot within 7 feet and sank that birdie try. Woods did not hit a fairway the rest of the way as he hit just four of 14 fairways on the day.
Woods scrambled to four straight pars, but his poor driving caught up with him at the 17th. His tee shot went way right and bounced back towards the fairway after hitting a hospitality tent. He left his second shot short in a bunker and was unable to get up-and-down for par. He two-putted from the fringe at the last for a round of even-par 70.
'I hit it so good this morning it was scary.' said Woods. 'I didn't miss one single shot and consequently I made three straight birdies. Then I come out here (for round three) and played like an idiot.'
Woods will likely extend his lead as the No. 1 golfer in the world as the two players who could have passed him in the rankings, Ernie Els and Vijay Singh, are well back. Singh is tied for 36th after a 3-under 67, while Els is tied for 72nd.
Toms, the 2001 PGA champion, collected three birdies over a four-hole stretch from the second. However, he mixed a bogey in at the par-4 fourth. He moved within two shots of the lead with a birdie at the 14th.
Toms pulled his drive way left at the last. His second remained in the rough and his third came up just short of the putting surface. Toms pitched on before two-putting for double bogey to drop to minus-6.
DiMarco picked up three birdies over his first 10 holes to climb to 6 under. He bogeyed the 13th, before birdieing the 15th for a share of second place.
'I was able to birdie three of the par-3s, and that's usually going to help you,' DiMarco said. 'Three twos on the card usually is pretty good. I made some really good par savers too.'
Jerry Kelly fired a 6-under 64 to move into a tie for eighth place. He is joined there by Charles Howell III (68), Angel Cabrera (67) and Luke Donald (65). Todd Hamilton, Robert Allenby, Bob Tway and Lee Westwood are one stroke further back at minus-3.